(Il)Legality of VIAIR 90C compressor?

Hey all, I’m assuming I’m wrong but I was checking the spec sheet of the VIAIR 90C and it seems to only be rated for 120 PSI, which is below that required 125 PSI for R82.

Was there an exception or am I misreading something? As far as I know this has been the default compressor since 2011 and the minimum 125 PSI rule has been there just as long, common sense says that FIRST wouldn’t give rookies illegal hardware.

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I believe that rule means that if 125 PSI were applied to it, it wouldn’t explode or something. The AndyMark compressor you linked is rated to output around 120 PSI, and can handle more than the 125 PSI required by R82.

R82 (2019)
All pneumatic items must be COTS pneumatic devices and either:
A. rated by their manufacturers for pressure of at least 125psi (~862 kPa), or
B. installed downstream of the primary relieving regulator (see R89), and rated for pressure of
at least 70psi (~483 kPa)
Any pressure specification such as “working,” “operating,” “maximum,” etc. may be used
to satisfy the requirements of R82.
It is recommended that all pneumatic items be rated by their manufacturers for a working
pressure of at least 60 psi (~414 kPa).

VIAIR 90C’s rating by the manufacturer is “Max. Working Pressure: 120 PSI”. I really don’t see how that fits with “All pneumatic items must be COTS pneumatic devices … rated by their manufacturers for pressure of at least 125psi”. I hope I’m wrong though.

Nice find!

Working pressure is usually less than maximum pressure.

That said, a Q&A to two places does seem to be in order. First, to Viair with “do you have a spec sheet with the maximum pressure on it, NOT the working pressure listed on sheet X?” Second, to FRC Q&A with “so, uh, this compressor you give the rookies doesn’t appear to meet this rule. What are we missing, or should there be an exception made?”

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Interesting. I just scrolled through, you’re right that it isn’t listed as rated to that. However, I just looked through the 2019 game manual, and it has this regulation on air compressors multiple times:

image

I wonder if compressors are exempt from R82?

Under “Operating Instructions” they have:

IMPORTANT: Always operate the compressor at or below the MAXIMUM PRESSURE RATING of the compressor. Please refer to Application & Specifications Sections of this manual for details.

So while it may not explode at 120 PSI that really sounds like the max pressure for typical operation.

I’ve sent an e-mail to FIRST though, I’d send it through the QA system as I’m a co-coach for my team but it’s thoroughly out of scope for the pre-rules.

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this thread already exists and has been solved. Working pressure and burst/intermittent pressure are two different things. Pneumatic items must have a 125psi burst pressure to be on the storage side of the system, the 90C meets this requirement.

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Good find! Evidently my search terms weren’t good enough.

That really only applies for 2011-2018 though, since language explicitly allowing the KOP items for the pneumatic system was absent in the 2019 game manual (2018 R83: The only pneumatic system items permitted on ROBOTS include the items listed below: A. Items available in the KOP…).
So as far as I can tell the compressor that shipped in the 2019 KOP was not legal to use in the 2019 season (though I’m sure the language would have been added if anyone submitted a QA)

That said I think it’s wrong to have an exception to the rules because a company is a sponsor (aka something only being legal because it’s in the KoP). Especially the pneumatics rules

Additionally I don’t think that having an intermittent pressure above 125 PSI qualifies them to be legal (and if it does then they should include “intermittent” explicitly in the blue box relating to general pressure ratings). I very much doubt any other pneumatic component would fly with the same conditions: An air tank that didn’t have 125 PSI working pressure, but had above 125 intermittent pressure I would not allow on my robot, and I assume would be a valid reason to not pass inspection. Even if it is I also find issue that there is no documentation available at all on the manufacturer’s site for it’s intermittent pressure rating and usage (I don’t have any data if, for instance, 2.5 minutes continuous qualifies as “intermittent”). Especially since they emphasize to never run the compressor above it’s max rating (120).

That is incorrect based on the rules.
image

The blue box under R81 explicitly states that any pressure may satisfy the requirements in R81.

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I believe grammar is causing us to disagree.
Correct me if I’m wrong but I believe you read the blue box as “Any type of pressure specification listed by the manufacturer may be used to satisfy the above. Three examples of which are ‘working’, ‘operating’, and ‘maximum’.”

I read it as “Any pressure specification listed by the manufacturer which is similar to (but not necessarily exactly the same as) ‘working’, ‘operating’, or ‘maximum’ is sufficient to satisfy the above”.

The reason is that I read it the second way is because there are types of pressure ratings that I don’t believe are sufficient to satisfy “In order to maintain safety, the rules in this section (10.9: Pneumatic systems) apply at all times while at the event, not just while the ROBOT is on the FIELD for MATCHES.”
For instance, if a team put a pressure tank with a burst pressure rating of 125 PSI onto their robot before the regulator I would not willingly stand next to them in queue or let my students do so, let alone expect them to be passed by a inspector. I also do not believe that “Intermittent” is sufficiently similar to ‘working’, ‘operating’, or ‘maximum’ (all of which I would classify as “continuous” and “Indefinite” [within the normal lifespan of the device] criteria) to be allowed under my reading.

There is no way to be certain which the GDC meant without a QA response, but I know which set of parts I’ll be allowing on my student’s robots.

You are correct the inspector may deem that illegal but not on the basis of R81, it would be illegal on the basis of R9 but I would argue they would need to have more evidence that the tank is unsafe at the operating conditions of FRC.
image

However if you go back to 2017 you can see that the wording even more explicitly allowed burst pressure of 125psi.
image

My understanding is that Burst pressure rating for most pneumatic devices is the pressure at which the manufacturers believes the item will continue to work after being exposed to that pressure and brought back down to it’s working pressure. The items may break above that pressure normally leaking or failing a sensor or deforming in some way. I don’t know of any devices that catastrophically fail in a dangerous manner when exposed to their burst pressure rating.